Re: Weird distorted shapes

I'm afraid the picture of the board is of the prototype... not the one exhibiting the problem.

-Douglas

> On Mar 5, 2014, at 12:25 PM, "SPW" <ishagi@netzero.com> wrote:
>
> The smaller one looks like a 1/4watt. The larger one looks like a 1/2watt.
> But schematic has both marked as 1/2watt. (though different ohmic value)
>
> FWIW.
>
>
> ---------- Original Message ----------
> From: Joel Griffin Dodd <griffindodd@gmail.com>
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Weird distorted shapes
> Date: Wed, 5 Mar 2014 08:54:40 -0800
>
> Rodger, could you expand on that a little so I can understand it more.
>
>
>> On Wed, Mar 5, 2014 at 7:34 AM, Rodger Boots <rlboots2@gmail.com> wrote:
>> Try running WITHOUT R14 & R72.
>>
>> Doesn't look like correct parts are on the board.� If these are low enough in value they could cause what you have.
>>
>>
>>> On Tue, Mar 4, 2014 at 2:44 PM, Joel Griffin Dodd <griffindodd@gmail.com> wrote:
>>> Here's the full schem for the Deflection and HV...
>>> http://www.dsbelec.iinet.net.au/Amp_Defl&HV_Schematic_Dez_FINAL.jpg
>>>
>>> And here is a high res photo of the deflection board if it is of any help...
>>> http://www.amazingarcading.com.au/2013_Proto-03.jpg
>>>
>>> Here's the parts list for the deflection board...
>>> http://www.dsbelec.iinet.net.au/deflection_pcb_a201015.htm
>>>
>>>
>>>
>>>> On Tue, Mar 4, 2014 at 12:39 PM, Colin Davies <colin.w.davies@btopenworld.com> wrote:
>>>> As Clay says....
>>>> �
>>>> �To be more useful I'd want to see the schematic for the
>>>> deflection section and/or the layout. �Curvey/distorted things like that
>>>> could be related to opamp speeds or outputs getting too close to the rails
>>>> or L/C or maybe power...
>>>> ----- Original Message -----
>>>> From: Joel Griffin Dodd
>>>> To: vectorlist@vectorlist.org
>>>> Sent: Tuesday, March 04, 2014 8:21 PM
>>>> Subject: Re: VECTOR: Weird distorted shapes
>>>>
>>>> I spoke to Doug Snyder from Atari who, apart from designing the System II hardware, also worked on a fair bit of the XY drives and outputs for many of their games. He said that there was cross talk between the Axis which is what was causing the curving and to isolate a letter on the scope then measure the voltage change for a stroke to see if there are unwanted voltage changes in the direction of the stroke that should remain straight. If there are non then it could be the yoke, if there are then the concern is that there is cross talk in the XY drives.
>>>>
>>>> Trouble is I have no idea how to isolate the stroke of one letter on my scope as I'm not that proficient.
>>>>
>>>>
>>>>
>>>>> On Tue, Mar 4, 2014 at 12:07 PM, Colin Davies <colin.w.davies@btopenworld.com> wrote:
>>>>> The problem looks more apparent in this other picture... �See how the 'straight' lines have a curve to them...
>>>>>
>>>>> https://www.dropbox.com/s/i1r76l4dif9vv2w/2014-03-02%2020.10.19.jpg
>>>>>
>>>>>
>>>>> ----- Original Message ----- From: "Clay Cowgill" <c.cowgill@comcast.net>
>>>>> To: <vectorlist@vectorlist.org>
>>>>> Sent: Tuesday, March 04, 2014 6:46 PM
>>>>> Subject: RE: VECTOR: Weird distorted shapes
>>>>>
>>>>>
>>>>>> >Look at this screen shot of another builders results...
>>>>>>> https://www.dropbox.com/s/owa3vq5l6f0lgv2/100_3343_zps3521fb63.jpg
>>>>>>>
>>>>>>> Notice the blue is perfectly formed, but the green is all messed up
>>>>>>
>>>>>> That looks to me as though the green channel amp is slow to turn on. �The
>>>>>> vectors look pretty straight-- they're just either 'fading in' (or 'fading
>>>>>> out' depending on the direction of the draw I suppose) before reaching the
>>>>>> end of the line. �Could be a tube issue as well. �Looking at the green color
>>>>>> output vs. a deflection channel (or two) would probably show the problem on
>>>>>> a scope.
>>>>>>
>>>>>> There might be a little high frequency 'jitter' in there somewhere that's
>>>>>> causing the hash on some of the green verticals. �Hard to tell with a
>>>>>> picture-- really need video there. �Also could just be that the shadow
>>>>>> mask/dot pitch on the tube is pretty big and sometimes the green verticals
>>>>>> are straddling the mask and appearing on one side or the other.
>>>>>>
>>>>>> For Joel's original problem, I would probably try to trace things through
>>>>>> the deflection section with the scope-- put the Star Wars boardset X output
>>>>>> on one channel and then follow X through the deflection section with the
>>>>>> other channel. �Set the volts/div to try to keep the waveforms about the
>>>>>> same vertical size on the scope and compare them visually. �You should be
>>>>>> able to see that amount of difference/distortion on the screen so you should
>>>>>> be able to see when it appears in the deflection board. �(Hard to debug
>>>>>> without knowing the design, but I'm assuming there's probably some sort of
>>>>>> pre-amp that you could look at before it gets to a power-amp stage.)
>>>>>>
>>>>>> It does kinda look like its more prominent on short vectors which is
>>>>>> probably a clue. �To be more useful I'd want to see the schematic for the
>>>>>> deflection section and/or the layout. �Curvey/distorted things like that
>>>>>> could be related to opamp speeds or outputs getting too close to the rails
>>>>>> or L/C or maybe power...
>>>>>>
>>>>>> -Clay
>>>>>>
>>>>>>
>>>>>> ---------------------------------------------------------------------------
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>>>>>
>>>>> ---------------------------------------------------------------------------
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>
>
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Received on Wed Mar 5 15:10:12 2014